Hi, here i have a problem with this task... I have a table "cancellation" which stores cancelled bookings and details of charges etc and a table "bookings" which stores details of bookings, for example:
cancellation(cancellation_id, booking_id, charge) booking(booking_id, customer_id, product_package_id, details) in the query, i wish to find, how many customers have booked for each product_package_id. if there were 3 bookings for product_package_id=1, and all these are cancelled and therefore exist in cancellation, then the query result shoud display something like package_id, #of bookings 1 0 here are what i tried select distinct b.product_package_id, count (distinct b.customer_id and not exists (select cc from cancellation cc where cc.booking_id=b.booking_id)) from booking as b group by b.product_package_id and it doesnt work. the syntax within the DISTINCT is wrong, unsurprisingly. i also tried select distinct b.product_package_id, count (distinct b.customer_id not in (select cc from cancellation cc where cc.booking_id=b.booking_id)) from booking as b group by b.product_package_id it produced incorrect result. ie, for those canceled bookings are also counted, producing package_id, #of bookings 1 3 which supposed to be package_id, #of bookings 1 0 could anyone give any hints please, many thanks ! -- View this message in context: http://www.nabble.com/nested-select-within-a-DISCTINCT-block-tf2272951.html#a6310575 Sent from the PostgreSQL - sql forum at Nabble.com. ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
